TK
4161
CM
1919
General Lighting
Safety Orders
UC-NRLF
Issued by the
Industrial Accident Commission
of the
State of California
525 MARKET STREET, SAN FRANCISCO
Effective December 1, 1919
CALIFORNIA STATE PRINTING OJTIC1
SACRAMENTO
1919
General Lighting
Safety Orders
Issued by the
Industrial Accident Commission
of the
State of California « «
525 MARKET STREET, SAN FRANCISCO
Effective December 1, 1919
CALIFORNIA STATE PRINTING OFFICE
SACRAMENTO
1919
(7800
INDUSTRIAL ACCIDENT COMMISSION
OF THE STATE OF CALIFORNIA
525 Market Street, San Francisco
423 Union League Building, Los Angeles
, Chairman.
A. H. NAFTZGER,
Commissioners.
H. M. WOLFLIN,
Superintendent of Safety.
SUMMARY OF THE SAFETY PROVISIONS
of the
Workmen's Compensation, Insurance and Safety Act.
Being Chapter 176 of the Laws of 1913 as Amended by Chapter 607 of the
Laws of 1915, and Chapter 586 of the Laws of 1917.
Sections 33 to 54, inclusive, of the Workmen's Compensation, Insur-
ance and Safety Act give the Industrial Accident Commission power to
make and enforce safety orders, rules and regulations, to prescribe safety
devices, and to fix safety standards. It also empowers the Commission
to appoint advisers who shall, without compensation, assist the Com-
mission in establishing standards of safety. The Commission may adopt
and incorporate in its general orders such safety recommendations as it
may receive from such advisers.
The Commission, carrying out its plan of obtaining the
best practical ideas to incorporate in its Safety Orders, asked
various interests to serve on a committee to draft Tentative
General Lighting Safety Orders.
COMMITTEE ON GENERAL LIGHTING SAFETY OEDEBS.
ROMAINE W. MYERS (chairman), consulting engineer (electrical and
illuminating), representing the National Council of Defense, Divis-
ional Committee on Lighting.
L. E. VOTER (vice chairman), illuminating engineer, General Electric
Company, representing the Association of Electrical Manufacturers
and the Lighting Fixture Association.
W. W. HANSCOM, electrical and mechanical engineer, representing the
National Electric Light Association, Pacific Coast Section.
SMITH O'BRIEN, architect, representing the American Institute of
Architects.
R. H. FENKHAUSEN, electrical engineer, Bethlehem Shipbuilding Corpo-
ration, Union Plant, representing the American Institute of Electrical
Engineers.
DANIEL C. MURPHY, president California State Federation of Labor.
PAUL SCHARREXBERG, secretary-treasurer California State Federation
of Labor.
R. S. PRUSSIA, illuminating engineer, Westinghouse Lamp Company,
representing the Association of Electrical Manufacturers.
MILES F. STEEL, Benjamin Electric Manufacturing Company, repre-
senting the Association of Electrical Manufacturers.
S. J. LISBERGER, Engineer, San Francisco District, Pacific Gas and
Electric Company, representing the Pacific Coast Gas Association.
CHAS. M. MASSON, illuminating engineer, Southern California Edison
Company, representing the Illuminating Engineering Society.
CONSTANT MEESE, Meese & Gottfried Company, representing the San
Francisco Chamber of Commerce.
F. DOHRMANN, JR., Nathan-Dohrmann Company, representing the San
Francisco Chamber of Commerce.
HARRY GORMAN, field agent, representing the Bureau of Labor Statistics.
H. B. WOODILL, president Woodill & Hulse Electric C9mpany, Inc.,
representing the Merchants and Manufacturers Association of Los
Angeles.
W. A. CHOWEN, manager California Inspection Rating Bureau, repre-
senting the Casualty Underwriters Board of California.
D. AYRE, superintendent inspection department, California Inspection
Rating Bureau, representing the Casualty Underwriters Board of
California.
HAROLD MESTRE, representing the Industrial Welfare Commission.
ROBT. L. ELTRINGHAM, electrical engineer, representing the Indus-
trial Accident Commission.
JOHN R. BROWNELL (secretary), superintendent of safety, Industrial
Accident Commission.
Acknowledgment is made of the assistance rendered by the Illuminating
Engineering Society in the preparation of these General Lighting Safety
Orders, and for the use of the various cuts which they kindly loaned.
M48977
GENERAL LIGHTING SAFETY ORDERS.
Order 1500. Definitions.
(a) Candle (or candlepower) means the unit of luminous
intensity maintained by the national laboratories of the United
States, France and Great Britain.
(b) Lumen means the unit of luminous flux, and is the
quantity of light necessary to produce an average intensity of
illumination of one foot-candle over an area of one square foot.
(c) Foot-candle means the unit of illumination equal to one
lumen per square foot. It is the lighting effect produced upon
an object by a lamp of one candlepower at a distance of one
foot.
(d) Photometer means a standardized instrument suitable
for making illumination measurements.
(e) Lamp means that part of the lighting equipment from
which the light originates.
(/) Local lamps (or lighting) means lighting units located
close to the work, and intended to illuminate only a limited
area about the work.
(g) Overhead lamps (or lighting) means lighting units
installed above ordinary head-level to secure a general illumi-
nation over a considerable area.
(h) Brightness means the intensity of light per unit area
emitted from, or reflected by, a body ; and in these Orders
is expressed in candlepower per square inch.
(i) Glare means any brightness within the field of vision of
such a character as to cause discomfort, annoyance, interfer-
ence with vision, or eye fatigue.
(j) Eyestrain means a physiological condition of the eye
resulting in discomfort, poor vision, or fatigue.
(k) Shaded means that the lamp is equipped with a reflector,
shade, enclosing globe, or other accessory for reducing the
brightness in certain directions, or otherwise altering or chang-
ing the distribution of light from the lamp.
(I) Illumination means the quantity of light received upon
a surface ; it is measured in foot-candles or in lumens per square
foot of area.
(m) Intensity of illumination means the quantity of light
received upon a surface, expressed in foot-candles or in lumens
per square foot of area.
GENERAL LIGHTING SAFETY ORDERS. 5
(n) Foot-candles at the work means the intensity of illumi-
nation on the object upon which work is being performed.
(0) Foot-candles at floor-level means the intensity of illumi-
nation on the floor of the space specified.
Order 1501. General Requirements.
(a) Working or traversed spaces in buildings or grounds
of places of employment shall be supplied during the time of
use, with either natural or artificial light in accordance with
the following Orders (1502-1509).
Order 1502. Natural Lighting.
(a) Windows, skylights or other roof-lighting construction
of buildings shall be arranged with the glass area so appor-
tioned that at the darkest part of any working space, when
normal exterior daylight conditions obtain (sky brightness of
1.50 candlepower per square inch) there will be available a
minimum intensity equal to twice that of Order 1503, other-
wise artificial light of intensities specified in Order 1503 shall
be provided.
(&) Awnings, shades, diffusive or refractive window glass
shall be used for the purpose of improving daylight conditions
or for the avoidance of eyestrain wherever the location of the
work is such that the worker must face large window areas
through which excessively bright light may at times enter the
building.
NOTE. — The intensity requirements for adequate day lighting are much
higher than those for adequate night lighting, because in general under
daylight conditions the light reaching the eye from all surroundings in the
field of vision is much brighter than at night, and hence a correspondingly
more intense light must fall on the object viewed.
Order 1503. Artificial Light.
(a) When the natural light is less than twice the minimum
permissible intensities of illumination set forth in the following
table, artificial light shall be supplied and maintained in
accordance with the table.
NOTE. — See Appendix for intensities recommended for best working
conditions.
Foot-candles at the floor level
1. Roadways and yard thoroughfares 0.02
2. Storage spaces, stairs, stairways, halls, hallways,
passageways, aisles, exits and elevator en-
trances 0.25
3. Water-closet compartments, toilet rooms, wash-
rooms, dressing rooms and elevator cars 0.50
b GENERAL LIGHTING SAFETY ORDERS.
Foot-candles at the work
4. Work not requiring discrimination of detail, such
as handling material of a coarse nature, and
performing operations not requiring close
visual application 0.50
5. Eough manufacturing requiring discrimination of
detail, such as rough machining, rough assem-
bling, rough bench work, also work in base-
ments of mercantile establishments requiring
discrimination of detail 1.00
6. Rough manufacturing requiring closer discrim-
ination of detail, such as machining, assembly
and bench work, also work in basements of
mercantile establishments requiring closer dis-
crimination of detail, intermediate between
5 and 7 2.00
7. Fine manufacturing, such as fine lathe work, pat-
tern and tool making, also office work, such as
accounting and typewriting 3.00
8. Special cases of fine work, such as watchmaking,
engraving and drafting 5.00
9. Processes otherwise safeguarded in which light is
detrimental i 0.00
NOTE. — Some exceptions to the intensity rule :
(a) There are some operations that are performed in compar-
ative darkness, as for example, photographic processes in the
dark room.
(6) There are some operations that are best observed by their
own light, as in parts of the process of working glass.
(c) Some^ operations are best observed by the "silhouette"
method of lighting in which the work is seen against a lighted
background in a comparatively dark room, as in some processes of
working with dark threads and lamp filaments.
In all such cases in which work is of necessity carried on in
comparative darkness, special precautions should be taken to
properly safeguard the workmen.
Order 1504. Measurements.
(a) For the purpose of light measurements, a standardized
photometer, certified by the Industrial Accident Commission of
the State of California, shall be used, and such measurements
shall be made at the locations specified in the table.
Order 1505. Shading of Lamps for Overhead Lighting.
(a) Lamps suspended at elevations above eye level less than
one-quarter their distance from any positions at which work
is performed, or where places are traversed, must be shaded in
such a manner that the intensity of the brightest one-quarter
square inch of visible light source shall not exceed seventy-five
candlepower per square inch.
GENERAL LIGHTING SAFETY ORDERS. 7
NOTE. — The following diagram illustrates the application of the above
rule, the distances being explanatory and representing the ratio between
the height of the lamp above the eye level and its horizontal distance
from the eye.
L /nz -7
L a/npj be/o w the l/rr?/ there shown ft 02 td/s fa/rt
must" be 3O -shaded thaf the. Casrd/e
Power o fthe brtghfes t£ 3<p s/f. of
the L tfhf' Jot/rce sho//fro /" e /r c eed work i '5 pc- r-
75CS? per jy. /sr. forsn e d
^~- ~~^~ *TT Limited height
Exception. Lamps suspended at elevations greater than
twenty feet above the floor are not subject to this requirement.
NOTE 1. — Glare from lamps or unduly bright surfaces produces eye-
strain and increases the accident hazard. The brightness limit specified
in this Order is an absolute maximum. \7ery much lower brightness
limits are necessary in many interiors illuminated by overhead lamps, if
the illumination is to be satisfactory. In some cases the maximum
brightness should not exceed that of the sky (two to three candlepower
per square inch).
NOTE 2. — Where the principal work is done on polished surfaces, such
as polished metal, celluloid, varnished wood, etc., it is desirable to limit
the brightness of the lamps in all downward directions to the amount
specified in this Order.
NOTE 3. — For method of measuring brightness, see Appendix, para-
graph 86.
Order 1506. Shading of Lamps for Local Lighting.
(a) Lamps for local lighting must be shaded in such a
manner that the intensity of the brightest square inch pre-
sented to view from any position at which work is performed,
shall not exceed three candlepower.
NOTE. — In the case of lamps used for local lighting, at or near eye
level, the limits of permissible brightness are much lower than for lamps
used for overhead lighting, because the eyes are more sensitive to strong
light received from below, and because such light sources are more
constantly in the field of view.
Order 1507. Distribution of Light on the Work.
(a) The reflectors or other accessories, mounting heights and
spacings employed with lamps shall be such as to secure a
reasonably uniform distribution of illumination, avoiding
8 GENERAL LIGHTING SAFETY ORDERS.
objectionable shadows and sharp contrasts of brightness. If
local lighting is used, there shall be employed in addition a
moderate intensity of overhead lighting, with a minimum of
not less than one-fourth (J) foot-candle.
Exception. "Where the light from the local lamps falls
principally upon surfaces which are white or nearly so, and
the ceilings and walls of the rooms are light, there is often a
sufficient general illumination received indirectly by reflection
to obviate the necessity of additional overhead lighting.
NOTE. — When local lighting is used as the sole source of illumination
of an interior, the field of illumination from each lamp is in contrast to
the surrounding darkness, thereby causing eyestrain and increasing the
accident hazard.
Order 1508. Emergency Lighting.
(a) Emergency lights shall be provided in all workspace
aisles, stairways, passageways, exits, outside landings of fire
escapes and other structures, used as regular or emergency
means of egress. These emergency lights are to provide for
adequate illumination when, through accident or other cause,
the regular lighting is extinguished.
NOTE 1. — It is the intention of this Order to guard against accident
due to the failure of the regular lighting system, by providing sufficient
illumination to enable the occupants to :
(a) Avoid contact with moving machinery and other danger points
until the regular lighting is again placed in operation.
(6) To vacate the building safely a
necessary because of fire or other causes.
.
(6) To vacate the building safely and expeditiously when this is
NOTE 2. — Emergency lighting may be installed in various ways. The
method to be employed depends upon the size of the premises, the extent
of the hazards of employment, and the means available for supplying
such emergency lighting.
(&) Emergency lighting systems, including all supply and
branch lines, their runways, raceways and supports, shall be
entirely independent of the regular lighting system, and shall
be lighted concurrently with the regular lighting system and
remain lighted throughout the period of the day during which
artificial light is required or used.
(c) Emergency lighting shall have a minimum intensity of
one-fourth (J) foot-candle. The emergency illumination shall
not exceed fifty (50) per cent of the distributed illumination.
(d) Emergency lighting systems shall be supplied from a
source independent of the regular lighting system in theaters,
public meeting halls, moving picture exhibition places, hospitals,
schools, and any other place where the nature of the hazard is
such as to require it, except where an exemption is granted by
GENERAL LIGHTING SAFETY ORDERS.
the Industrial Accident Commission. This source of supply
and controlling equipment shall be such as to insure the reliable
operation of the emergency lighting system when, through acci-
dent or other cause, the regular lighting system is extinguished.
Where a separate source of supply can not be obtained for the
emergency lighting, the feed for emergency lighting must be
taken from a point on the street side of the service equipment.
AY here source of supply for the regular lighting system is an
isolated plant within the premises, an auxiliary lighting system
of sufficient capacity to supply all emergency lighting must be
installed from some other source, or suitable storage battery;
or separate generating unit may be considered the equivalent
of such service.
Order 1509. Switching and Control Apparatus.
(a) Switches or other controlling apparatus shall be so
installed that pilot or night lights may be controlled from a
point at the main entrance, and/or other easily accessible points.
Pilot or night lights may be a part of the emergency lighting
system.
(&) All switching and control apparatus on emergency,
pilot and night lights shall be plainly labeled for identification.
NOTE. — The purpose of this Order is to make it possible for the night
watchman or other qualified persons to turn on enough lamps, when
entering any portion of the premises at night, to enable them to safely
see their way around without the need of a lantern or flashlight.
>-47f
10 GENERAL LIGHTING SAFETY ORDERS.
APPENDIX.
GENERAL INFORMATION AND SUGGESTIONS.
1. The foregoing orders give in the briefest possible form the
minimum requirements of lighting in factories, mills and other
work places to insure reasonable safety to workmen from
accident and injurious eyestrain. General information with
detailed discussion of the methods of applying the orders and
of obtaining adequate illumination to insure efficient production
are 'presented in this Appendix.
2. When adequate and satisfactory illumination is substi-
tuted for the all too prevalent poor illumination in factories,
mills and other work places, the results obtained are mutually
beneficial to the employees, the employers, and the country as
a whole. Under proper illumination conditions, the health,
contentedness, safety and skill of the employees are maintained
at a high standard, the output is increased in quantity and
improved in quality, while there is a proportional reduction in
the cost of each unit of finished products when it reaches the
public.
3. While it is desirable to have adequate light over the
working areas, it is absolutely essential for the proper results
to eliminate or minimize the light which otherwise would pass
directly from the lamps to the eyes of the workers ; that is, one
must avoid glare which is not only fatiguing to the eye but
also conducive to the incorrect estimation of sizes and locations
of objects in the field of view.
4. Glare effects may be caused not only by the light reaching
the eye directly from the sources having a brightness greatly
in excess of that of the objects viewed, but they may be pro-
duced by excessive reflection from the objects within view. In
factory lighting each lamp should be so located that the eye
does not see it in the ordinary course of work, and so shaded
or covered that brilliant reflections are avoided. The desired
result can be obtained by putting over the lamp an open shade
which screens it and reflects downward much of the light which
would otherwise be of either no value or actually detrimental.
Another way of accomplishing the same result is to surround
the lamp with a diffusing globe dense enough not to reveal the
form of the actual light source within, but to give the effect of
GENERAL LIGHTING SAFETY ORDERS. 11
the light pouring from the globe as a whole. Specific sugges-
tions for various locations are contained in this Appendix.
5. In the following descriptive matter may be found the
elements of good illumination versed in such manner that it
can be understood readily by the nontechnical mind. A
perusal of this subject will convince one that, aside from the
humanitarian standpoint, the expense incurred in obtaining
satisfactory lighting will, in practically all cases, result in good
financial returns.
6. Minimum and desirable illumination. The minimum
foot-candles in Order 1503 specify the lowest illumination with
which the employee can be properly safeguarded against acci-
dent. It is to the advantage of the employer to provide the cor-
responding intensities of modern practice listed in the follow-
ing table of desirable illumination, as such provision results in
reduced eyestrain, greater accuracy of workmanship, increased
production and less spoilage.
Desirable Illumination.
Foot-candles
at floor level Corresponding
• — modern minimum —
practice Order 1503
1. Roadways and yard thor-
oughfares 0.05 to 0.25 0.02
2. Storage spaces 0.50 to 1.00 0.25
3. Stairs, stairways, halls, hall-
ways, passageways, aisles,
exits, elevator entrances
and elevator cars 1.00 to 2.00 0.25-0.50
4. Work not requiring discrim-
ination of detail 1.00 to 2.00 0.50
5. Rough manufacturing re-
quiring discrimination of
detail 2.00 to 4.00 1.00
6. Rough manufacturing re-
quiring closer discrimina-
tion of detail 3.00 to 6.00 2.00
7. Fine manufacturing, ac-
counting, typewriting 4.00 to 8.00 3.00
8. Special cases of fine work___ 7.00 to 15.00 5.00
12 GENERAL LIGHTING SAFETY ORDERS.
7. Table of Recommended Intensities for Detailed Operations and
Processes. (Expressed in foot-candles.)
Classification.
Assembling.
Rough assembling 2-6
Medium assembling 3-9
Fine assembling 4-12
Extra fine assembling 7-15
Automobile manufacturing.
(See machine shops, paint shops, woodworking shops, etc.)
Bakeries.
Mixing and baking 3-9
Banks.
Clerical and private offices 4-12
Desk and cage lighting 4-12
General illumination 1-3
Barber shops 4-12
Boiler, engine rooms and power houses.
Boiler rooms 2-4
Coal and ash handling 2_4
Engine rooms 3-9
Auxiliary equipment 2-6
Oil switch and transformer rooms 3-9
Switchboards 3-9
Storage battery rooms 2-6
Brewing, distilling and bottling.
Beer boiling 2-6
Bottling 3-9
Clearing or resting and fermenting 1-3
Cool ship 1-3
Keg washing 3-9
Keg filling 3-9
Buffing and polishing.
Medium work 3-9
Fine work 4-12
Button manufacturing.
Grading machines, wet and dry polishing 1-3
Grinding machines, cutting blanks and shells, card-
ing buttons, hand turning, automatic machines 3-9
Sorting of waste, sorting for thickness 3-9
Grading for color and defects 7-15
GENERAL LIGHTING SAFETY ORDERS. 13
Classification.
Candy making.
Cooking over furnaces 3-9
Cooling slabs 3-9
Cream beater machines 3-9
Dipping (hand) 3-9
Dipping (machine) 3-9
Moulding 3-9
Revolving pan 3-9
Spinning bench 3-9
AWights and measures 3-9
Wrapping and packing 3-9
('•ii'inng and preserving.
Cooking 3-9
Assorting, cleaning, cutting and peeling 3-9
Hand filling .__ 3-9
Machine filling 3-9
Chemical works.
Furnaces 2-6
Tanks or cooking, extractors, percolators, nitrators- 3-9
Generators and stills 2-6
Drying 2-4
Evaporators 3-6
Filtration 3-6
Grinding 3-9
Crystallizing 3-6
Bleaching 3-6
Electrolytic cells 3-9
Clay products and cements.
Enameling 3_9
Grinding 2-4
Filter press rooms 2-4
Moulding and pressing 3-6
Cleaning and trimming 3-6
Coloring and glazing 4-12
Kiln rooms 2-4
Kiln yards -J-2
Cloth products. £fif £&*
Cutting 4-12 7-15
Sewing (machine) 4-12 7-15
Si-wing (hand) 4^-12 7-15
Pressing __^ 4-12 7-15
Inspecting 4-12 7-15
Cl«>th treating (oilcloth, etc.) 3-9 4-12
14 GENERAL LIGHTING SAFETY ORDERS.
Classification.
Construction — Building, railway, tunneling, etc.
Indoor 1-3
Outdoor £-2
Dairy products.
Separators, evaporators, churns, moulds and presses 3-9
Pasteurizing 3-9
Bottling, canning and labeling 3-9
Ice cream freezers 3-9
Depots.
Baggage rooms 1-2
Dining rooms 3-6
General offices 4-8
Waiting rooms 2-4
Loading platforms 1-2
Draughting rooms 7-15
Electric manufacturing.
Coil and armature winding 4-12
Mica working 4-12
Insulation moulding 4-12
Other insulating processes 4-12
Storage battery moulding of grids 3-9
Lamp manufacturing 7-15
Wire insulating 4-12
Elevators.
Freight and passenger 1-3
Fertilizer manufacturing.
Cookers, pressers, fertilizer dryers, fertilizer mills- 2-6
Forge shops and welding.
Rough forging 2-6
Fine forging 3-9
Drop forging 3-9
Foundries.
Rough moulding 2-6
Fine moulding 3-9
Core making 3-9
Charging floor 2-4
Tumbling and cleaning 2-6
GENERAL LIGHTING SAFETY ORDERS. 15
Classification.
Glass works.
Mix room 2-6
Furnace room 2-6
Casting and lehr 2-6
Grinding 3-9
Fine grinding and polishing 4-12
Glass-blowing machines 3—9
Cutting glass to size 3-9
Glass cutting (cut glass) 7-15
Beveling 4-12
Silvering 3-9
Inspecting 7-15
Etching and decorating 4-12
Glove manufacturing. goods. goods.
Sorting 1 4-12 7-15
Cutting 3-9 4-12
Stitching 4-12 7-15
Trimming and inspecting 4-12 7-15
Pressing 3-9 4-12
Knitting 3-9 4-12
Grinding, buffing and polishing.
Rough work 2-6
Medium work 3-9
Fine work 4^-12
Halls, stairways, passageways and aisles 1-2
Eat manufacturing. £•£ ££
Forming, sizing, pouncing, flanging, finish-
ing and ironing 3-9 4-12
Dyeing and stiffening 2-6 3-9
Braiding 2-6 3-9
Cleaning and refining 2-6 3-9
Sewing 4-12 7-15
Hospitals.
Corridors 0.5
"Wards, general (supplemented by local) 0.5
Wards, with no local lighting 1-3
Laboratories , 3-6
Operating tables 25-40
(See boiler and engine rooms, laundries, kitchens,
dining rooms, storage spaces, etc.)
16 GENERAL LIGHTING SAFETY ORDERS.
Classification.
Hotels.
Kitchens 2-6
Dining rooms 3-6
(See engine and boiler rooms, offices, storage spaces,
stairways, passageways, laundries, etc.)
Ice making 2-6
Inspecting.
Rough inspecting 2-6
Medium inspecting 3-9
Fine inspecting 4—12
Extra fine inspecting 7-15
Jewelry and watch manufacturing.
Bench work and extra fine machine work 7—15
Machine work 7—15
Stamping 7-15
Engraving 7-15
Jewel working 7-15
Laundries and dry cleaning.
Sorting and marking 3-9
Washing 2-6
Mangles and machine ironing 3-9
Pressing and hand ironing 3—9
Dry and steam cleaning 3-9
Leather manufacturing.
Cleaning, tanning, stretching, etc 2-6
Cutting, fleshing and stuffing 3-9
Finishing and scarfing 4-12
Vats 1-3
Leather working. £*£ *££
Grading and matching 4—12 7-15
Cutting and scarfing 4r-12 4-8
Sewing 4-12 7-15
Pressing and winding 3-9 4r-12
Libraries 3-6
(See other classifications relating to corresponding
quarters. )
Locker, toilet and wash rooms^^ : - 2-4
GENERAL LIGHTING SAFETY ORDERS. It
Classification.
Machine shops.
Rough bench and machine work 2-6
Medium bench and machine work 3-9
Fine bench and machine work 4—12
Extra fine bench and machine work 7—15
Automatic machines (ordinary) 3-9
Automatic machines (fine) 4-12
Grinding, buffing and polishing, rough work 3-9
Grinding, buffing and polishing, medium work 4-12
Grinding, buffing and polishing, fine work 7-15
Meat packing.
Slaughtering 2-6
Cleaning and cutting 3-9
Cooking 3-9
Grinding and packing ^ 3-9
Canning 3-9
Milling and grain food products.
Cleaning 2-6
Grinding or rolling 2-6
Baking or roasting 3-9
Mining.
(See boiler and engine rooms, power houses, halls,
stairways and passageways, roadways, yard thor-
oughfares, etc.)
Offices 4-12
Oil refining.
(See boiler and engine rooms, power houses, road-
ways, yard thoroughfares, chemical works, etc.)
Packing.
Rough 2-6
Medium 3-9
Fine 4-12
Paint manufacturing 2-6
Paint shops.
Dipping or spraying 3-9
Rubbing 3-9
Firing 2-6
Hand painting and finishing, ordinary 3-9
Hand painting and finishing, fine 4^12
Hand painting and finishing, extra fine (automobile
bodies, piano cases, etc.) 7-15
3-47806
18 GENERAL LIGHTING SAFETY ORDERS.
Classification.
Paper 'box manufacturing. &>oas. goods.
Cutting 2-6 3-9
Machine folding 2-6 3-9
Hand folding 2-6 3-9
Pasting and assembling 2-6 3-9
Paper manufacturing.
Beaters 2-6
Calendering 3-9
Machine 3-6
Grinding 2-6
Finishing, cutting and trimming 4-12
Plating.
Plating 3-9
Polishing and burnishing 3-9
Printing industries.
Linotype and monotype 7-15
Typesetting 7-15
Composing stone 7-15
Matrix and casting 3-9
Miscellaneous machines 3-9
Proofreading 4-12
Presses, job and small automatic 3-9
Presses, rotary, flat-bed, etc 3-9
Lithographing 4-12
Electrotyping 4-12
Engraving 7-15
Receiving and shipping 2-6
Restaurants (see hotels).
Roadways and yard thoroughfares 0.05-0.25
Rubber manufacturing and products.
Calendering 3-9
Grinding 3-6
Vulcanizing 3-6
Washing and compounding rolls 3-9
Schools.
Auditoriums 2-4
Blackboards 3-5
Classrooms, study rooms, libraries, laboratories 3-9
Gymnasiums '. 3-6
Sewing, drafting 7-15
Shop work (rough) 2-6
Shop work (fine) 4-12
Stairways, corridors, toilets, hat and cloakrooms, etc. 1-2
Storage spaces 0.5-1
GENERAL LIGHTING SAFETY ORDERS. 19
Classification.
Sheet metal working.
Bench work, ordinary 3-9
Bench work, fine 4-12
Punches, presses, shears, stamps and welders 4-12
Spinning 4r-12
Miscellaneous machines 3-9
Shipbuilding.
( See machine shops, sheet metal working, roadways,
yard thoroughares, woodworking, assembling, etc.)
07 , Light Dark
Shoe manuactunng. goods, goods.
Inspecting and sorting raw material 4-12 7-15
Cutting 4-12 4-8
Stitching, machine 7-15 7-15
Stitching, hand 4-12 7-15
Lasting and welding 4-12 4-8
Hand turning 3-9 3-9
Miscellaneous bench and machine work 3-9 4-12
Soap manufacturing.
Kettle houses 2-6
Framing 1-3
Cutting 2-6
Stamping, wrapping and packing 3-9
Soap chip 2-6
Soap powder 2-6
Filling and packing soap powder 3-9
Stairways (see halls) .
Steel and iron mills, bar, sheet and wire products.
Automatic machines 3-9
Charging floor 2-4
Casting floor 2-4
Soaking pits and reheating furnaces 2-4
Rolling mills 3-9
Shears, presses, punches and riveters 3-9
Rod mill 3-9
Wire drawing, coarse 3-9
Wire drawing, fine 4-12
Pickling and cleaning 2-6
Stone cutting.
Machine cutting 2-6
Hand cutting 2-6
Carving 3-9
Polishing 3-9
20 GENERAL LIGHTING SAFETY ORDERS.
Classification.
Store and stock rooms.
Rough stock 2-6
Medium stock 3-9
Fine stock 4r-12
Stores.
(Satisfactory store lighting requires that considera-
tion be given so many different factors, such as
location, color of finish, size and shape, location
and character of displays, as to make it impossible
to compile a complete list. The following tabu-
lation is general, only, and it is recommended that
expert advice be obtained where any doubt exists
as to the proper allowances to be made.)
Automobile showrooms - 3-9
Art (light on exhibits) 5-10
Book 3-9
Baker 2-6
Butcher 2-6
China 3-9
Cigar 4-6
Clothing 4-12
Cloak and suit 4-12
Candy 3-6
Confectionery 3-6
Decorator 4r-12
Department (see each department).
Drug 2-6
Dry goods 4-12
Florist 2-6
Furniture 3-9
Furrier 4-12
Grocery 2—6
Haberdasher (men's furnishings) 4-12
Hardware 2-6
Hat 4-12
Jewelry 4-12
Millinery 4-12
Music 2-6
Notions 3-9
Piano 3-9
Rug racks 10-20
Shoe 2-6
Stationery 2-6
Tailor 4-12
Tobacco (see cigars).
GENERAL LIGHTING SAFETY ORDERS. 21
Classification.
Sugar refining.
(See boiler and engine rooms, power houses, halls,
passageways, chemical works, etc.)
Telegraph.
Operating __ 4-12
Telephone.
Automatic exchanges 4-12
Manual exchanges 3-9
Testing.
Rough 2-6
Medium 3-9
Fine 4-12
Extra fine 7-15
Textile mills.
n Light Dark
OOttOn — goods. goods.
Opening and lapping 2-6 2-6
Carding 2-6 2-6
Drawing frame - 2—6 2—6
Roving, spooling, spinning, etc 3-9 3-9
Warping 2-6 2-6
Slashing 2-6 2-6
Drawing in 3-9 3-9
Weaving 3-9 3-9
Dyeing 3-9 3-9
Silk—
Winding 3-9 3-9
Throwing 3-9 3-9
Quilling and warping 3-9 4-12
Weaving 3-9 4-12
Dyeing 3-9 3-9
Finishing 3-9 4-12
Woolen —
Picking 3-9 3-9
Washing and combing 3-9 3-9
Carding 2-6 2-6
Twisting 3-9 3-9
Dyeing 3-9 3-9
Drawing in 3-9 4-12
Warping 3-9 4-12
Weaving 4-12 7-15
Perching 7-15 7-15
Knitting machines, ordinary and nappers 3-9 3-9
Knitting machines, flat and others 4-12 4-12
Cordage mills __, 3-9 3-9
22 GENERAL LIGHTING SAFETY ORDERS.
Classification.
Tin can manufacture.
(See sheet metal working, machine shops, etc.)
Tobacco products — all operations 3-9
Warehouses 2-4
(See other classifications.)
Woodworking.
Rough sawing (sawmills) 2-6
Sizing, planing, rough sanding, etc 3-9
Machine woodworking, medium 3-9
Machine woodworking, fine 4-12
Bench work, medium 3-9
Bench work, fine 4-12
Fine sanding and finishing 4-12
Gluing and veneering 3-9
Cooperage 3-9
DAYLIGHT.
8. Importance of daylight. Adequate daylight facilities
through large window areas, together with light, cheerful
surroundings, are highly desirable and necessary features in
every work place, and they should be supplied through the
necessary channels not only from the humane standpoint, but
also from the point of view of maximum plant efficiency. The
unusual attention to gas and electric lighting in factories, mills
and other work places during the past few years ; the perfection
of various lamps and auxiliaries by means of which an improved
quality and quantity of lighting effects are obtained; and the
care which has been devoted to increasing the efficiency in
various industrial operations — all go to emphasize the many
advantages and economies that result from suitable and ade-
quate window space as a means for daylight in the proper
quantities and in the right directions during those portions of
the day when it is available.
9. Three considerations. Three important considerations of
any lighting method are sufficiency, continuity and diffusion.
With respect to the daylight illumination of interiors, suffi-
ciency demands adequate window area; continuity requires
(a) large enough window area for use on reasonably dark days,
(6) means for reducing the illumination when excessive, due to
direct sunshine, and (c) supplementary lighting equipment for
GENERAL LIGHTING SAFETY ORDERS. 23
use on particularly dark days and especially toward the close
of winter days; diffusion demands interior decorations that are
as light in color as practicable for ceilings and upper portions
of walls, and of a dull or mat finish in order that the light
which enters the windows or that which is produced by lamps,
may not be absorbed and lost on the first object that it strikes,
but that it may be returned by reflection and thus be used over
and over again. Diffusion also requires that the various sources
of light, whether windows, skylights or lamps, be well distrib-
uted about the space to be lighted. Light colored surroundings
as here suggested result in marked economy, but their main
object is perhaps not so much economy as to obtain a result
that will be satisfactory to the human eye.
10. Requirements. The following requirements may now be
listed for natural lighting:
1. The light should be adequate for each employee.
2. The windows should be so spaced and located that daylight
conditions are fairly uniform over the working area.
3. The intensities of daylight should be such that artificial
light will be required only during those portions of the day
when it would naturally be considered necessary.
4. The windows should provide a quality of daylight which
will avoid a glare due to the sun's rays and light from the sky
shining directly into the eye, or where this does not prove to
be the case at all parts of the day, window shades or other
means should be available to make this end possible.
5. Ceilings and upper portions of walls should be maintained
a light color to increase the effectiveness of the lighting facil-
ities from window areas. The lower portions of walls should
be somewhat darker in tone to render the lighting restful to the
eye. Factory green or other medium colors may be used to
good effect.
11. Classification. Means for natural lighting may be
classed under three broad divisions as follows :
(a) That case in which the windows are located on the sides
of the building or in the framework of saw-tooth construction
where diffused light from the sky reaches the work during a
large portion of the day.
(&) That case in which windows are located overhead on a
horizontal or nearly horizontal plane in the form of skylights,
24 GENERAL LIGHTING SAFETY ORDERS.
thus furnishing direct light from the sky during a large portion
of the day.
(c) That case in which prismatic glass takes up the direct
light from the sky and redirects it into the working space.
Method (a) is, of course, the most common of the three, and
it may be noted that the saw-tooth or other roof -lighting con-
structions have become very popular and result in an excellent
quality and quantity of light for given window areas, provided
the size and location of windows are in accord with modern
practice.
12. Increasing the value of floor space. Adequate and well
distributed natural light means that certain portions of the
floor space which ordinarily would not be available for work,
are converted into valuable manufacturing space. In a gen-
eral way, therefore, the average factory, mill or other work
place, if properly designed, should possess natural lighting
facilities which produce the best practicable distribution of
daylight illumination.
13. Wide aisles. With low ceilings and very wide aisles,
workmen located at the central portion of the building must
sometimes depend for their natural light on windows located
at a considerable distance away from their working position.
In these cases it may be possible, in general, to depend alto-
gether on daylight over an entire floor space, even at those
times of the day when daylight conditions would be entirely
adequate under other circumstances. This statement applies
to side windows rather than to skylights or to saw-tooth con-
struction. Fig. 1 illustrates this feature.
14. Varying conditions. In a case of this kind, employees
located next to the windows are furnished with suitable day-
light in the early morning and towards the latter part of the
afternoon, the upper portions of the windows being particu-
larly serviceable in lighting areas at some distance away from
the windows. A southern exposure, however, results in such
excessive light from the sky during the middle of the day, that
heavy shades are nearly always pulled down so as to cover the
entire window area. This plan makes it necessary to use arti-
ficial light throughout the larger part of the office during the
brightest portion of the day, and reduces the daylight at those
points where it would supposedly be the best, namely, near the
GENERAL LIGHTING SAFETY ORDERS.
25
windows. Here the location of the windows is a large factor
in the excellence of the daylight conditions, but the manipula-
tion of the shades is perhaps even more important. To avoid
such difficulty, adjustable translucent upper window shades
with adjustable opaque lower shades might be employed.
REGION OFCOM-
PARITIVE ABSENCE
OF DAYLIGHT. ARTI-
FICIAL DAYLIGHT
REQUIRED NEARLY
ALL DA.Y
ELEVATION
0
/DESKS-,
000
0 O 0
0 O 0
-50'
000
PLAN
FIG. 1. Diagram of a large office
with windows on one
side only.
15. Upper portions of windows. It should be further noted
in this illustration that the upper portions of the windows give
a reduced illumination in proportion to their areas, to the floor
space near them. In rooms of moderate size, therefore, the
windows should be placed as near the ceiling as practicable.
When the sun shines* through windows so located, the direct
light must be reduced or diffused. This may be accomplished
by the use of ribbed glass in ordinary factory and mill build-
ings, and in offices by the use of translucent sunshades or
awnings.
16. Tempering the light. The light due to the sunshine on
such shades and awnings will be as bright as ordinary skylight
if the shade is well chosen, and the ribbed glass will be still
brighter. If the windows are large, the illumination is likely
4— 478C6
26
GENERAL. LIGHTING SAFETY ORDERS.
to be too great near the windows as previously pointed out and
it should be reduced. This should not be done, however, by
pulling down an opaque shade over the top of the windows
because the top portion of the window is the part that is par-
ticularly needed to give light to the interior of the room. The
better scheme is to employ an opaque shade which should be
raised from the bottom of the window. This will reduce the
illumination near the window without affecting it over the
interior of the room to any marked degree.
17. Bench locations. Fig. 2 shows how benches are com-
monly located with respect to windows, so that the light received
on the work may be most satisfactory. This sets a certain
< CEILING-* | 7Q.
BENCH SURFACE- ] ASSEMBLY WORK;
^^~" \
"1 /
}„„,„>;;,„, '<
ELEVATION
'!
1
"VBENCH-I -i -u
li
I
•+ J
(
!
•
1]
1
*• -
V-BENCH-, 1 -
* l
1
///S//SS/S/////J//)
PLAN
FIG. 2. Diagram showing benches located
with respect to the windows so
as to receive the natural light
advantageously.
limitation upon the possible arrangement of the work over
the floor space, depending on the way daylight is furnished to
the floor area. This limitation can be eliminated almost com-
pletely in the case of artificial light through a uniform dis-
tribution of lamps overhead. This statement applies to those
cases where natural light is transmitted through side windows,
and includes a feature specially noticeable in buildings of more
than one story. In contrast, the work may be arranged almost
independently of the natural light in buildings where the
natural light is furnished by overhead windows or through
the means of saw-tooth construction.
18. Window glasses. Both translucent and clear glass are
employed for factory and mill windows. There is a slight
reduction in the transmitted light through ordinary translucent
GENERAL LIGHTING SAFETY ORDERS. 27
vvire glass, but it is often required by insurance regulations
for a deduction in the fire risk where a given building is located
in close proximity to other buildings. Wire glass is also used
quite generally with steel window frames, here being an added
protection from the standpoint of fire risk. Wire glass may
be obtained in clear form, but its expense in contrast to the
translucent form is such as ordinarily to prohibit its use for
industrial purposes.
19. Wire glass. Wire glass, also known as ribbed glass,
should be used and is advocated for practically all factory and
mill windows where prisms are not required. Wires of rather
open mesh cause so little reduction in light as to warrant no
mention of this .feature. Special care should be taken to get
such glass as is smooth both on the flat side and on the ribbed
side to facilitate cleaning. Wire or ribbed glass gives better
diffusion than plain glass.
20. Prism glass. Where the sky outside of the windows is
obstructed by buildings, prism glass is recommended if the room
is deep. Different kinds of prisms can not be used to advan-
tage interchangeably. The amount of prism glass required
in any case depends much upon the surroundings and to obtain
excellent results, of which such glass is capable, it must be
used intelligently.
21. Skylights. Skylights are sometimes installed in long
narrow continuous strips in a sloping roof. The ribs of the
ribbed glass are generally so arranged that it is convenient
to make them at right angles to the length of the strips. The
result is that the sunshine is diffused by the ribs over a narrow
area parallel to the strip of skylight, thus lighting one part
of the room much more brilliantly than the remainder. If the
ribs are installed to run parallel to the strips, they will give
a much more general distribution of the sunlight. In the
foregoing, the word strip refers to the long belt of skylight and
not to the individual sheet of glass. Ribbed glass in vertical
windows should generally be placed with the ribs horizontal.
They thus roughly fulfill some of the functions of prisms.
22. Dirt accumulations. While translucent wire or ribbed
glass reduces the amount of light transmitted through the
windows, the roughness of the outside surface of such glass
often causes accumulations of dust and dirt, which are more
28 GENERAL LIGHTING SAFETY ORDERS.
to blame for the reduction of transmitted light in some cases
than the translucent nature of the glass itself. Remedies of
this difficulty are to secure smooth glass and to resort to
frequent cleaning.
23. Wire glass as a safeguard. Wire glass for skylights is,
of course, a practical necessity as a safeguard against accidents
due to accidental breakage of the glass or due to objects falling
on top of the glass.
24. Sunshine not desirable. In all the work of providing
natural light, it should be kept in mind that direct sunshine
in itself, from the illumination standpoint, but irrespective of
sanitary conditions, is not wanted. The idea that sunshine is
the important item is a common but an erroneous impression.
For example, in saw-tooth construction, the windows do not
face the south to get all the sunshine possible, but they face
the north to exclude the sunshine. Ordinarily windows, on
the other hand, face all directions because not enough light
can be distributed to interiors from north windows alone.
Windows on the other than north fronts admit sunshine to be
sure, and this makes sun shades and awnings necessary to
exclude the excessive brightness.
VALUE OF ADEQUATE ILLUMINATION.
25. Factory and mill owners are concerned in the matter
of securing the largest output for a given manufacturing
expense. An improved machine tool capable of increasing
the product for given labor costs is most attractive, provided
its first cost is within returnable limits out of the larger profits.
Improved small tools, better methods of handling material,
adequate crane service, fire protection, good shop floors,
accurate and efficient timekeeping methods, and similar items,
vitally concern the shop manager ; money is expended to realize
excellence in these features because they afford increased
economies and protection, thus resulting in a higher efficiency
of the plant.
26. Energy consumption a minor item. Many arguments
leading to the sale of gas and electric lamps for use in factory
and mill buildings are based on reducing the lamp operation
cost of substituting a new for an older system. Arguments
of this kind are of value, however, only when such a reduction
GENERAL LIGHTING SAFETY ORDERS. 29
in operation cost can be effected without sacrifice in the ade-
quacy of the illumination. It would be a poor policy, in the
extreme, to argue a saving in energy consumption by the sub-
stitution of one type of lamp for another on a basis of equal
candlepower in both old and new systems.
27. Effect of good light on production. Arguments of a
convincing nature, which insure to the factory or mill man-
ager an increased output through improved illumination
service, are of importance and even greater at times than
reductions in the cost of illumination for the same quantities
of light. In view of the fact that resulting advantages of
superior illumination on increased output are apt greatly to
exceed economies in operation cost as regards the lighting
system, it is a distinct advantage to direct and hold the atten-
tion on the former rather than on the latter. This statement
will be more apparent when interpreted into definite items
as follows:
28. Advantages of good light. While the necessity of good
natural and artificial light is so evident that a list of its effects
may seem commonplace, these same effects are of such great
importance in their relation to factory and mill management,
that they are well worth careful attention. The effects of good
light, both natural and artificial, and of bright and cheerful
interior surroundings, include the following items:
1. Reduction of accidents.
2. Greater accuracy in workmanship.
3. Increased production for the same labor cost.
4. Less eyestrain.
5. Promote better working and living conditions.
6. Greater contentment of the workmen.
7. More order and neatness in the plant.
8. Supervision of the men made easier.
In this list it will be noted that items 4, 5, 6, 7 and 8 all have
a bearing on accident prevention.
29. Interpreting the advantages of good light. While the
major consideration in the eyes of the factory or mill owner
is undoubtedly and quite naturally the money value of good
light in the larger return of both quantity and quality of work
which may result from the installation of a superior as com-
pared with an inferior lighting system, it should be noted that
it is very difficult to interpret into dollars and cents the value
30 GENERAL LIGHTING SAFETY ORDERS.
of good light made possible by such returns. This difficulty
is due to the necessity of keeping all conditions in a factory or
mill section absolutely constant while varying the amount of
illumination from poor to good conditions, in an effort to
determine the output and its dependency on the light facilities.
As accurate data becomes available, giving the increases in
production for certain specific improvements in artificial light-
ing, it will doubtless prove helpful to a proper interpretation
of adequate light and its worth to any plant.
The eight foregoing points are emphasized as forming the
most important features in the problem of good lighting.
Although difficult to interpret into money values, and some-
what intangible, they are indisputable arguments in favor of
the best available illumination from the standpoint of the
factory or mill owner.
30. Practical example. Continuing from the manufacturer 's
point of view, it may be said that certain assumptions as to
energy cost, cleaning, interest and depreciation, show that the
annual operation and maintenance cost for the illumination
of a typical shop bay of 640 square feet area, may be taken
at $50.00. If five workmen are employed in such a bay at an
average wage of say 25 cents per hour, the gross wages of the
men in such a bay, plus the cost of superintendence and indi-
rect shop expense, may equal from $5,000 to $7,000 per annum.
In a case of this kind, therefore, the lighting will cost from
•fa to 1 per cent of the wages, or the equivalent of less than
4 to 6 minutes per day. We may roughly say that a poor
lighting system will cost at least one-half this amount (some-
times even more through the use of inefficient lamps and a poor
arrangement of lamps), or the equivalent of say 2 to 3 minutes
per day. Nearly all factories and mills have at least some
artificial light, hence, in general, if good light enables a man
to do better or more work to the extent of from 2 to 3 minutes
per day, the installation of good lighting will easily pay for
the difference between good and bad light, through the time
saved for the workmen.
31. Actual losses. Superintendents have stated in actual
instances, that due to poor light their workmen have lost much
time, sometimes as much as from one to two hours per day on
certain days. If good light will add an average of say one-
half an hour per day to the output, these 30 additional effective
GENERAL LIGHTING SAFETY ORDERS. 31
minutes represent an increase in output of 5 per cent, brought
about through an expenditure equal to \ of 1 per cent of the
wages for improved lighting, or a saving equal to ten times the
expense.
OLD AND NEW LAMPS.
32. The inadequate means available for illumination by
artificial methods in the past have contributed to the slowness
of an appreciation of the features of artificial light which
influence the working efficiency of the eye. Open flame gas
burners, carbon incandescent and arc lamps, practically the
only illuminants available ten years or so ago, play but a
small part in the present approved methods of factory and
mill lighting.
33. New lamps. The large variety of comparatively new
lamps available for factory and mill lighting includes the
mercury vapor, tungsten, gas-filled tungsten, metallic flame
or magnetic arc, the flame carbon arc, the quartz mercury
vapor, and various types of gas arc lamps. Remarkable
improvements have thus been made in both the electric and
gas lighting fields, the same general rules of applying the
lamps covering both of these fields. Possibilities in factory
and mill lighting are now attainable which, before the intro-
duction of these new lamps, were either unthought of or
impossible. Consideration of the eye as a delicate organ,
together with the new ideas of the items which affect its comfort
and efficiency, have resulted in establishing certain principles
in illumination work, and have directed attention naturally
and in a growing manner to the proper use and application of
these new lamps.
EFFECTS ON FACTORY AND MILL LIGHTING PRODUCED
BY MODERN LAMPS.
34. With the introduction of these new gas and electric
lamps, broader possibilities have been presented in factory
and mill lighting. The use of units of sizes adapted to the
purposes, allows results which it has been hitherto impossible
to obtain satisfactorily, either by the arc lamp, carbon filament
or open flame gas burner, formerly available.
32 GENERAL LIGHTING SAFETY ORDERS.
35. New possibilities. It is evident that the introduction of
the many new lamps has made possible what may be termed
a new era in industrial illumination, a distinctive feature of
which is the scientific installation of the lighting units, suiting
each to the location and class of work for which it is best
adapted. Before the availability in recent years of medium
sized gas and electric units the choice of the size of unit for
a given location was often no choice at all. In many cases, due
to small clearance between cranes and ceilings, or other con-
ditions making it necessary to mount the lamps very high above
the floor, but one size or type of unit was available, the carbon
filament or open flame gas burner in the former, and the arc
lamp in the latter case.
36. Low ceilings. For low ceilings, up to 18 feet, the use
either of carbon filament, open flame gas burner, or arc lamps
resulted usually in anything but uniform light over the work-
ing plane, and often produced merely a low general light
which was practically useless for the individual machine. In
such instances, individual lamps had to be placed over and close
to the machines. With this arrangement, a relatively small
area is lighted by each lamp and the metal shades usually
employed serve only to accentuate the "spot lighting" effect.
Such a form of illumination for factory and mill work is
unsatisfactory and inefficient, but, as stated, was in the past
in many cases the only available scheme. The absence of
lamps of the proper size is no longer an excuse for the exist-
ence of such conditions in industrial plants.
GENERAL REQUIREMENTS OF ARTIFICIAL LIGHTING.
37. The following requirements for factory and mill lighting
are made all the more important by the peculiar limitations and
the wide variety of conditions to be found in factory and mill
buildings and in factory and mill work :
1. Sufficient illumination should usually be provided for
each workman irrespective of his position on the floor
space.
2. The lamps should be installed and selected so as to
avoid eyestrain to the workmen.
3. The lamps should be operated from sources of supply
which will insure reliable illumination results, particularly
on account of the demoralizing effect by intermittent
service, just when the light may be most needed.
GENERAL LIGHTING SAFETY ORDERS. 33
4. Adequate illumination should be provided from over-
head lamps so that sharp shadows may be prevented as
much as possible, and in such measure that individual
lamps close to the work may be unnecessary except in
special cases.
5. The type and size of lamp should be adapted to the
particular ceiling height and class of work in question.
6. In addition to the illumination provided by overhead
lamps, individual lamps should be placed close to the work
if they are absolutely necessary in the eyes of a lighting
expert, and in such cases the lamps should be provided
with suitable opaque reflectors.
These requirements may now be met by means of the new
types of gas and electric lamps, one type of which can usually
be found for practically each factory and mill location, espe-
cially adapted to the general physical conditions of the location
as typified by the clearance between cranes and ceiling and
other similar items.
OVERHEAD AND SPECIFIC METHODS OF ARTIFICIAL
LIGHTING.
38. Factory and mill lighting may be classified under two
general divisions: First, distributed illumination furnished
from lamps mounted overhead ; and second, distributed illumi-
nation furnished by individual lamps located close to the work.
For practical purposes this classification is sufficient. In
numerous cases a combination of these two methods becomes
necessary.
39. Mounting the lamps high. Where the lamps are high
enough to be out of the line of ordinary vision, and are of a
size and so spaced as to furnish illumination at any position
on the floor where work may be carried on, the system is
referred to as the overhead method of lighting. This method
has many advantages. Its general adoption, which has been
somewhat slow, has increased with the appearance of the many
new types of lamps and with the growing appreciation of the
value of good lighting.
40. Where a small amount of general or overhead lighting
is coupled with specific lighting from. individual lamps, a large
part of the floor space in many shops is in relative darkness,
and much dependence must be placed on the hand lamps close
to the work. The small number of overhead lamps generally
34 GENERAL LIGHTING SAFETY ORDERS.
used in such cases furnishes merely a small amount of addi-
tional illumination over the floor space which is not sufficient
to be of much value. However, where sufficient intensity is
provided by general illumination, this is often a very effective
means of lighting a large workroom.
41. Low ceiling. Locations with low ceilings, until recently,
have been lighted by the individual hand lamp method, because
the old carbon filament lamps, being of low candlepower, could
not well be used close to the ceiling, while the old type of arc
lamp was often impracticable, due to its large physical size,
as well as its relatively high candlepower. This statement is
subject to some modification, because low candlepower units
have sometimes been used in clusters for low ceilings as a com-
promise between a single small or a single large unit, this
scheme being, however, usually insufficient and unsatisfactory
in comparison with modern methods of lighting. In a partic-
ular manner, therefore, suitable illumination has been difficult
with low ceilings.
42. New types of gas and electric lamps have a range of
candlepower from very low to very high values, and the over-
head system with the elimination of individual lamps is thus
possible ; in other words, a size of gas or electric lamp may now
be selected from a large available list of sizes for nearly every
factory or mill condition.
VARIOUS LOCATIONS ILLUSTRATED.*
43. Figs. 3 to 12 inclusive are given to indicate how the
problem of adequate illumination has been solved in a number
of actual instances, and the following notes apply to some of
the considerations involved.
There are two main items to consider in deciding for or
against high candlepower lamps for the factory or mill. First,
how high are the lamps to be mounted; and second, will the
light at any given point on the machines or other operations
be satisfactory if it comes from a few lamps or should it come
from many sources? If the ceiling or overhead construction
is under 16 feet, lamps of high candlepower can hardly be
used in sufficient numbers to produce uniform illumination
over the floor space. If they are to be mounted at a height
*Figs. 8 to 12 inclusive are, in general, arranged in the order of their
mounting heights. The low mounting heights are shown in the earlier
illustrations and the higher mountings in the later views.
GENERAL LIGHTING SAFETY ORDERS. 35
between 16 and 25 feet, it is largely a question of whether
light from a relatively few lamps will produce satisfactory
results. For mounting heights over 25 feet, lamps of high
candlepower possess some advantages, chief of which is their
large volume of light for given energy consumed, always pro-
vided the light is effectively directed towards the floor.
44. Three groupings. These three groupings by mounting
heights are conveniently shown in Figs. 15, 16, 17 and 18. In
Fig. 15, a single shop bay with a ceiling height of 12 feet is
shown as typical of the first grouping. The single high candle-
power lamp furnishes approximately the same amount of light
to the machines as do the eight small lamps. Note, however,
that the illumination from the large lamp is not nearly as
uniform as that from the small lamps, although the spacing
of both the small and the large lamps as represented in this
illustration is typical of many actual installations. Note also
that the shadows cast by the large lamp at certain portions of
the floor space must be so marked as to make the illumination
it furnishes very inferior in this respect to the illumination
from the smaller lamps, because of their larger number.
Here, if the number of large lamps for the given floor area
be increased in an endeavor to make the illumination more uni-
form and to reduce the shadows, the expense as compared with
that for smaller lamps, makes the large lamps a very unfavor-
able proposition. These two features are the basis for stating
that in general large lamps are not desirable for mounting
under 16 feet, and an analysis of conditions, together with
a. careful and unbiased comparison with the illumination
produced by smaller lamps, will nearly always bear out this
conclusion.
45. Second grouping. In Fig. 17, a 20-foot ceiling has been
selected as typical of the second grouping, a single shop bay
being shown. Here the work is assumed to be rough assembly,
mostly on horizontal surfaces, and the single high candlepower
lamp, besides giving more nearly uniform illumination, because
the light is distributed more broadly due to the increased
height, is correspondingly more satisfactory as to shadows
produced by the large lamp in the preceding illustration
(Fig. 15), on account of the improved direction in which much
of the light reaches the work. In this case, the arrangement
36 GENERAL LIGHTING SAFETY ORDERS.
of both large and small lamps is typical of many existing
installations.
46. In Fig. 16, however, although the height is the same as
in Fig. 17, the work is quite different, being conducted on the
inside of large vertical tanks. It would obviously be impos-
sible to perform this work by the light from the single large
lamp as Well as with that from the larger number of medium
sized lamps, even if the actual amount of light from each was
the same, on account of the poor direction of the light at cer-
tain positions of the work from a single unit in such a case.
The medium sized lamps furnish approximately the same
quantity of light and yet no matter where the tanks may be
placed, they will receive considerable light from the medium
sized lamps directly over or nearly over them, at least far more
than is apt to reach them from a single unit in every other
bay (the assumed arrangement of the large lamps).
47. For this second grouping of mounting heights, then, the
large lamps may or may not be adapted, depending on whether
the reduction of shadows is of much importance, as is the case
in Fig. 16. The large lamp is, however, more likely to be
satisfactory here than in the first case (Fig. 15), because of
the better distribution of the light due to the higher mounting,
a fact made evident in Figs. 15 and 17 on account of the
decreased number of small lamps and the increase in their
size made possible in Fig. 17 as compared with Fig. 15, where
the mounting is lower. By the same line of argument, it can
be shown that for higher mountings, large lamps are still more
likely to prove satisfactory.
48. In Fig. 16, the number of large lamps might have been
increased for the given floor area, but to have done so would
mean that the cost for the energy and upkeep to maintain
them would be excessive in comparison with the smaller types
of lamps.
GENERAL LIGHTING SAFETY ORDERS.
37
FIG 3 Night view of a rather low factory section showing tungsten lamps
of the 100-watt size in bowl reflectors mounted 13 feet above the
iloor.
FiG. 4. Night view showing lighting in low store section, 400-watt tungsten
lamp in 18-Inch dense semi-indirect bowls. Ceiling height 13 feet.
Note the comparative absence ef shadows.
38
GENERAL LIGHTING SAFETY ORDERS.
FIG. 5. An example of yard or alleyway lighting, 200-watt tungsten lamps in
reflectors with a mounting height of 20 feet. Note the evenness of
illumination and the absence of shadows. Twenty-five per cent of
the accidents in manufacturing plants are due to poor illumination.
6. Night view of a planing mill showing an installation of 250-watt
tungsten lamps with a 16 -foot mounting. Note the excellent dis-
tribution of the light and the comparative absence of shadows. This
is an example of the overhead method of lighting.
GENERAL LIGHTING SAFETY ORDERS.
39
FIG. 7.
Night view of factory section, 400-watt bowl type reflectors with
29-foot mounting height.
FIG. 8.
Night view of open hearth pouring floor with 750-watt reflectors,
35-foot mounting height and 40-foot spacing.
40
GENERAL LIGHTING SAFETY ORDERS.
FIG. 9. Night view of factory section with relatively high mounting of
250-watt tungsten lamps. The lamps are 20 feet above the floor.
Note the excellent distribution of the light and the shielding effect
of the girders which serve to reduce the glare as one looks down
the aisle.
FIG. 10.
Night view of arc lamp installation with 40-foot mounting at center
of picture and 20-foot at sides. Excellent distribution.
GENERAL LIGHTING SAFETY ORDERS.
41
FIG. 11. Day view of relatively high s««ti»n, showing a system of gas lighting.
FIG. 12.
High section showing a system of mercury-vapor lamps. Note the
excellent distribution of. light over the floor area.
42
GENERAL LIGHTING SAFETY ORDERS.
FIG. 13.
Bad lighting. Bare lamps produce a glare which Is harmful and
renders the Illumination very ineffective. Compare with Fig. 14.
Fio. 14. Example of good tungsten lighting.
GENERAL LIGHTING SAFETY ORDERS.
43
)W POWER
UNITS
HIGH POWER UNIT
ELEVATION
PLAN
FIG. 15. Diagram showing alternate
schemes for lighting a
low factory section.
This contrasts the use
of large and small
lamps for a mounting
height of 12 feet.
ELEVATION
'.LOW
POWER UNlTi
^ 4*
«JHIGH POWER UNIT £
i >BENCHES
*--4- 4 j 4
PLAN
FIG. 16. Diagram contrasting the
use of large and medium
sized lamps for mount-
ing height of 20 feet.
PLAN
FIG. 17. Diagram of same factory
space shown in Fig. 16,
but with a different class
of work. This view con-
trasts the use of large
and medium sized lamps
for a 20-foot mounting.
44
GENERAL LIGHTING SAFETY ORDERS.
49. Third grouping. In Fig. 18, the third grouping of
mounting heights is shown with the lamps about 50 feet above
the floor. In this illustration the distribution of the light
from the large lamps will be far more satisfactory, both for
flat and tall work than in the two preceding cases. It will be
noted further that the increased height of the lamp causes the
light to fall in such directions as to distribute it evenly over
CRANE RUN-WAY-
MACHINE TOOLS AND HEAVY ASSEMBLY
WORK LOCATED ON THIS FLOOR AREA'^
ELEVATION
[HIGH POWER UNIT
_BAYJNTER5EC1IPN:
-l6'-6"--->K 33-0"-- —
_ ; BAY INTERSECTION-... _J.
BAY INTERSECTION— « _i
'HIGH POWER UNIT
*-$ PLAN
FIG. 18. Diagram showing the use of large lamps
for a mounting height of 50 feet.
the entire floor space taken care of by this one lamp in much
better shape than for the lower mounting heights. (See also
Pigs. 19 to 23, inclusive.)
LIGHTING CIRCUITS FOR ELECTRIC LAMPS AND SUPPLY
MAINS FOR GAS LAMPS.
50. The question of lighting circuits is mentioned here with
particular reference to factory and mill conditions, where
motor loads are apt to be large in comparison to the energy
GENERAL LIGHTING SAFETY ORDERS.
45
consumption of electric lamps which are in service. In some
cases; the proportion of motor load to lighting .load is in the
ratio of 10 to 1, in others 7 to 1, and so on, and the varying
demands on the circuits by motors may greatly affect the lamps.
Hence it is important to maintain strictly separate supply
circuits for the lamps in order to avoid varying voltage which
is apt to result if the motors are connected to the same circuits
with the lamps.
MEZZANINE
FLOOR '
&
"o
k HIGH POWER*
UNIT
INCHES-. !
4-,8'-tf-J
T ---BE
; lAISLEl i |
ELEVATION
<- 40'-0- >
BENCH
|BENCH_!
VVHIGHPOWER9
>*- UNIT "£
BENCH
|BENCH ;
MEZZANINE
FLOOR
POWqR UNIT'
l^LOWPOWERTjNIT~5 ~°
BENCHES^
PLAN
FIG. 19. This shows a v e r y
poor arrangement
of artificial light-
ing by means of
large lamps mount-
ed too close to the
floor. Compare
this poor lighting
scheme with the
improved plan in
Fig. 20.
ELEVATION
40'-0"---.
— »
; TBENCH:
=0
•csi TBENCH
PLAN
FIG. 20. This illustration is
to be compared
with Fig. 19. It
Indicates an im-
proved scheme over
that shown in
Fig. 19 ; made pos-
sible by the use of
smaller lamps.
51. Constant voltage. In addition to the superior illumina-
tion resulting 'from lamps supplied from constant voltage
mains, some types operate with longer life or very much better
mechanically when supplied with constant voltage than other-
wise. These features will therefore generally more than offset
the somewhat greater cost of maintaining separate circuits for
each class of service. In like manner and for similar reasons,
it is advisable to place gas lamps on supply lines separate from
those delivering gas for power purposes.
CONTROL OF LAMPS AND ARRANGEMENT OF SWITCHES.
52. The control of lamps in factory and mill lighting is
important in all cases, but specially so where a large number
of lamps is used in preference to a small number for a given
46
GENERAL LIGHTING SAFETY ORDERS.
J ^
> AISLE
'-LOW POWER' UNITS*'
T ASSEMBLY
BENCH ! HERE
N^LOW POWER UNITSr'''
r ^BENCHu
I ; 1
\
AISLE | i |
1 \
J
ELEVATION
. 4
-T-
ELEVATION
<3£
z/
UJ '
(-00 ^
(
0-H
-4
r
. ii A
'** BENCH !
t ASSEMBLY4
H<- 16-0- -
*£ BENCH
=0
t A A A
BENCH '
^ JT'*' I t t "
^.Jo 1 BENCH
N-LOW POWER/UNITS '1'
^ASSEMBLY
•e IS'-Q1'---?
BENCH'S
<n /LOW^ POWER 'VU NITS
•4- JL-
BENCH
;
PLAN
Fia. 22.
Pi.AN
Fio. 23.
These three illustrations show various ways in which a factory space of 16 ft.
girder clearance can be handled, depending on the class of work performed.
The first case, Fig. 21, is fairly satisfactory for storage spaces, and either
the second or third cases, Figs. 22 or 23, can be employed for bench assembly
or manufacturing. The third case, Fig. 23, is to be preferred where the
class of work consists of the handling of small machinery parts.
GENERAL LIGHTING SAFETY ORDERS. 47
floor area. For example, where an overhead system of tung-
sten lamps of small size is used, a large number will, of course,
be necessary for a given floor area, and in such cases the
number of control circuits may at times seem excessive when
planned out for sufficient flexibility of operation. Such cir-
cuits, however, in rendering the system more flexible, will be
more than paid for by the saving in energy and maintenance
due to the turning out of lamps not needed in certain sections
of the factory or mill, provided the number of hours per day
during which the lamps are used on the average is relatively
large, and the differences in daylight intensities over the floor
area is also relatively large.
53. Control parallel to windows. The lamps most distant
from the windows will usually be required at times when the
natural light near the windows is entirely adequate, thus
making it an advantage to arrange the groups of lamps in
circuits parallel to the windows. The advantages of this
method are further apparent when it is considered that if the
lamps are controlled in rows perpendicular to the windows,
all lamps in a row will necessarily be on at one time, while
a portion only may be required.
54. Practical case. The foregoing statement may be devel-
oped into a definite proposition. Thus, to install a single
switch may involve say $5.00 as its first cost. If ten lamps are
to be controlled from a single switch, these ten lamps must
obviously either all be turned off at a time or all turned on
at a time. An additional switch at a cost of $5.00 will permit
either half of these ten lamps being turned off, if not required
at certain times when the remaining five are needed. This
extra switch may or may not be an economy. Consider, for
example, the case where these five lamps are of the 60-watt
tungsten type, and that they are turned off by the extra switch
on an average of one-half an hour per day while the others are
needed, or vice versa. In a year's time, the energy saved at
1 cent per kilowatt-hour, will amount to perhaps 50 cents.
At this rate it will require ten years for the energy saved to
pay for the first cost of the extra switch. This would not be
considered a distinct economy. If, however, the energy cost
be greater, and more nearly the average under actual con-
ditions, or if the number of hours per day during which a
48 GENERAL LIGHTING SAFETY ORDERS.
portion only of the lamps will not be used, be greater, then
these values will be correspondingly modified.
55. Locating switch-es and controls. In locating switches
or controls in factory and mill aisles, care should be exercised
to arrange them systematically, that is, on columns situated
on the same side of the aisle and on the same relative side of
each column. This plan materially simplifies the finding of
switches or controls, by those responsible for turning on and
off the lamps, and is particularly important where a given
floor space is illuminated by a large number of small or medium
sized lamps distributed uniformly over the ceiling area, a fea-
ture which is usually accompanied by the use of a relatively
large number of switches or controls.
SYSTEMATIC PROCEDURE SHOULD BE FOLLOWED IN
CHANGING A POOR LIGHTING SYSTEM OVER TO AN
IMPROVED ARRANGEMENT.
56. When undertaking the change from an old to a new
lighting system, the various forms of illumination which are
adapted to factory and mill spaces should be studied, and an
investigation made of the various types of gas and electric
lamps on the market which are available for the purpose.
57. Time should be allowed for a study of the given locations
to be lighted; for preparing the plans of procedure in the
installation of the gas or electric lamps and auxiliaries; and
for customary delays in the receipt of the necessary supplies
and accessories to the work in hand. Altogether, therefore,
work of this kind requires considerable time for its completion.
58. Using the shop force. In large factories or mills, a
wiring or gas-fitting force is sometimes a part of the mainte-
nance division. The work of the wiremen or fitters is likely
to be heaviest in the winter, due to the dark days. Where
this condition exists, there is all the more reason to apportion
out new work so as to accomplish it during the months of least
wiring and piping repair activity, and further, at that time
of the year when employees will be comparatively unaffected
by the disturbances usually associated with a change from an
old to a new lighting system through possible irregularities
in the illumination service while the wiremen or fitters are
at work.
GENERAL LIGHTING SAFETY ORDERS. 49
59. Distribution of expense. Another feature different
from the foregoing viewpoint is in the distribution of the
installation cost over a relatively long interval. If, for
example, the system is desired for the approaching winter, the
complete wiring or piping plans may be drawn up and blocked
out into three, four or even more sections, thus spreading the
expense over as many months.
60. Yearly appropriation. In some shops a given appro-
priation may be allotted each year for building equipment.
From the standpoint of finance plans, it may thus be desirable
to distribute outlays of this nature over the year, rather than
to concentrate them at any one time. An important consid-
eration in this method of installing lamps, however, is to
prepare in as far as possible the complete plans in advance,
at least as regards given factory or mill sections, so as to insure
a uniform and symmetrical installation as a whole when the
component parts are finished.
REFLECTORS AND THEIR EFFECT ON EFFICIENCY.
61. A reflector or shade is used in conjunction with a lamp
for the purpose of reducing the glare otherwise caused by
looking directly into the bare lamp, as well as for the purpose
of redirecting the light most effectively to the work.
62. Reflectors and shades, both metal and glass, are now
obtainable for each size of incandescent electric and gas lamp.
For a certain ratio between the spacing and the height of the
lamps, a reflector can nearly always be selected which will
furnish uniform illumination over the working surface.
63. Function of reflector. Owing to the direction of the
light from the lamp, nearly all types of lamps, in addition
to the downward light, furnish some rays which go upwards
and away in other directions from the objects to be illumi-
nated, and are therefore relatively not useful. Furthermore,
a bright source in the field of vision causes an involuntary
contraction of the pupil of the eye, which is equivalent to a
decrease in illumination in so far as the eye is concerned.
Hence, while reflectors or shades may at first seem to reduce
the amount of light in the upper part of the room, their use
actually increases the amount of light in a downward useful
direction, and improves the "seeing," due to the better con-
ditions which surround the eyes. The economic function of
50 GENERAL LIGHTING SAFETY ORDERS.
the reflector as contrasted to this easier condition it affords
the eyes, is to intercept the otherwise useless or comparatively
useless rays which do not ordinarily reach the work, and to
reflect them in a useful direction. In performing this func-
tion, there is a choice through the design of the reflector, in
the manner of distributing the light, so as to make the illu-
mination on the floor space uniform with certain spacing
distances and mounting heights as previously mentioned.
64. Avoiding dark spots. With the use of lamps for which
a large variety of reflectors is available, the proper reflector
should therefore be chosen so as to give the desired distribu-
tion of light. In other cases, as in the use of the gas or electric
arc lamps, where the globe or reflector is usually a fixed part
of the lamp, care must be exercised to space the lamps at
sufficiently close intervals to insure uniformity of the illumi-
nation, that is, a freedom from the relatively dark spaces
which exist between lamps when spaced too far apart.
65. Light interiors. With a light ceiling, the reflection of
that part of the light which passes through a glass reflector
to the ceiling, and which is added to the light thrown down-
ward from the under surface of the reflector, is a factor in
building up the intensity of the illumination on the working
surface. Great importance is therefore attached to light
interior colors, especially on ceilings and the upper portions
of walls, both in reinforcing the direct illumination, and in
giving diffusion, which in turn adds to the amount of light
received on the side of a piece of work. It should also be
stated that the intensity of the light from bare overhead
lamps when measured on the working surface may be increased
by as much as 60 per cent through the use of efficient reflectors.
This is due to the utilization of the horizontal rays of light
as previously stated, which predominate in the bare lamp,
whereas the most effective light in factory and mill work is
apt to be that which is directed downward.
66. Points to consider. Reflectors will not be classified here
from the commercial standpoint, but the following items should
be given consideration in the selection of the type of reflector
for factory or mill use :
1. Utilization efficiency. How much does the reflector
contribute to the effective illumination on the work?
2. The effect in reducing glare.
GENERAL LIGHTING SAFETY ORDERS. 51
3. Natural deterioration with age through accumula-
. tions of dust and dirt.
4. Ease in handling and uniformity of manufacture.
5. Physical strength and the absence of projections
which may increase the breakage in case of glass reflectors.
67. A study of the various reflectors on the market with the
aid of these items as a basis will determine what reflectors are
best adapted to given conditions. Regarding the third item
in the foregoing list, it may be stated that under comparative
tests in service, the accumulations of dust and dirt on glass
reflectors do not seem to be any greater than the coating of
dirt which accumulates on the inside of a metal reflector in
the same length of time.
SIDE LIGHT IMPORTANT IN SOME FACTORY AND MILL
OPERATIONS.
68. It has been customary in many cases to measure the
effectiveness of illumination in terms of the vertically down-
ward component of the light. This method has ignored the
value of side components in relation to vertical surfaces and
openings in the side of the work. It is sometimes more
necessary to light the side of the machine or the side of a
piece of work than the horizontal surface. If, then, in design-
ing a factory or mill lighting system, the prime object is the
production of the greatest amount of downward illumination,
it may happen that the side component is so small that the
sides of machinery or of work are inadequately lighted.
69. Two ways to secure side lights. Experience indicates
that there are two general ways in which to secure adequate
side lighting. One of these methods is to lower the lamps,
and the other is to use broader distributing reflectors than are
called for by the rules which consider uniformity of the down-
ward illumination only. Side walls or other reflecting surfaces
will modify the results. Thus, after the determination of a cer-
tain type of reflector for producing uniform vertically down-
ward illumination, it may be found that more side light is
necessary, and this extra side component may, as stated,
usually be secured by selecting a somewhat more distributing
reflector. Broader distributing reflectors are apt to result in
less downward illumination and will sometimes call for larger
lamps than found necessary by preliminary calculations.
52 GENERAL LIGHTING SAFETY ORDERS.
70. Practical case. As an illustration, in a certain lighting
system a vertically downward intensity of about 3 foot-candles
was deemed sufficient for the work involved. Measurements
and observations showed that the side light was insufficient.
In this particular installation it was found necessary to pro-
duce a vertically downward intensity of about 5 foot-candles
on the average in order to secure an intensity of about 2 foot-
candles on the side of the work, and also to use a somewhat
broader distributing reflector than at first chosen. Two foot-
candles on the sides of the work were sufficient in this case
where bench work and work in the vise on small machine parts
were conducted.
71. Keeping the lamps high. It is recommended that the
lamps be mounted near the ceiling in all reasonable cases
where side light is necessary, and that the side light be
increased, not by lowering the lamps, but through the medium
of broader distributing reflectors and larger lamps, if required.
This attitude is taken on account of the glare which results
when lamps are mounted too close to the work, a feature most
noticeable in the absence of a reflector or where glass reflectors
are used.
72. Maintenance. Provision should be made for systematic
upkeep of natural and artificial lighting.
73. Windows. Factory and mill windows become covered
in time with dirt, and produce greatly decreased values of
natural light in consequence. These losses may easily be great
enough to affect the workmen seriously, and to necessitate the
use of artificial light at times when otherwise it would not be
required. Dark surroundings also increase the likelihood of
accidents. Regular window cleaning should therefore be a
part of the routine of every factory and mill building or group
of buildings.
74. Lamps. Carbon filament, mercury-vapor, gas mantle
and tungsten lamps burn out or break, globes and reflectors
become soiled, and the various other items of deterioration
take place so gradually that in many cases they are given no
special concern in the practical economy of the shop. More-
over, it is hardly necessary to mention the fact that often
lighting systems are allowed to deteriorate to an extreme point
and nothing is done unless complaints come in from employees
GENERAL LIGHTING SAFETY ORDERS.
53
after the lighting facilities here and there throughout the shop
have become so poor that work has to be discontinued tempo-
rarily. The losses of time from such circumstances, when
added up throughout a year, are more than likely to exceed
the expense of systematic attention to such maintenance items
in advance.
75. Overhead system. Furthermore, with modern methods
where the lamps are usually mounted overhead rather than
close to each machine, the importance of relieving the workmen
from any care of the lamps, and placing it in the hands of a
maintenance department is even greater than has been the
case in the past, particularly in large plants.
76. Reflector cleaning. The serious loss of light when globes
and reflectors are allowed to go for long periods without
cleaning is shown in Fig. 25. This set of curves resulted from
a test on a glass reflector used with a tungsten lamp. The one
curve shows the value of the light given by the lamp at dif-
ferent angles when the lamp and reflector are clean, while the
smaller curve shows the enormous reduction of light after the
lamp and reflector have been in service for about four months
without being cleaned.
30°
FIG. 25.
15"
30-
Curves showing serious
losses of light from a
tungsten lamp and its
reflector, due to accumu-
lations of dirt. This is
a condition applicable
to all types of lamps, as
other illuminants suffer
corresponding losses
from dirt accumula-
tions.
77. In this particular case, which is a typical one, the loss
of light at the end of the four-month interval amounted to
about 50 per cent. The cost of electrical energy in this shop
54
GENERAL LIGHTING SAFETY ORDERS.
FIG. 26. Very poor lighting in a worsted goods factory. The wiring is badly
arranged, the contrasts between light and dark portions of the
room are excessive, and in some cases the wrong size of lamp is
used in a given reflector. The system is unsightly and represents
bad practice. Compare with Fiff. 27.
FIG. 27. Worsted mill with localized general illumination. This is an exam-
ple of excellent illumination with tungsten and metal reflectors.
Note the reflection from the goods to their ceiling. Compare with
Fiff. 26.
GENERAL LIGHTING SAFETY ORDERS.
55
FIG. 28. Very poor arrangement of arc lamps. The lamps are mounted to
one side of aisle over line shafting. Very little light reaches the
machinery to the right. Compare with Fig. 29.
FIG. 29. Well planned system of arc lighting. The lamps are high and above
the ordinary line of vision. Compare with Fig. 28.
56 GENERAL LIGHTING SAFETY ORDERS.
was such that the loss of light during the fourth month
amounted to about 12 cents, while the total cost of taking
down, washing and replacing this reflector amounted to
about 3 cents. The economy of a fairly frequent attention to
cleaning of such reflectors is at once apparent, even if the
improved condition of the light in itself be ignored.
78. The example just given will serve to illustrate the class
of upkeep problems which are involved in shop lighting. The
most forcible emphasis is applicable to the idea that system
may properly be called a first step towards success in this line
of maintenance work.
79. A method of inspection and maintenance. In one large
factory a regularly developed method of inspection and
renewals is employed. As an example, the method as applied
to several thousand tungsten lamps which are in service in
the various buildings will be described. All the lamps are
inspected once per day, except Saturday and Sunday. A
regular route is followed by the inspector, and all burned out
lamps, broken switches, loose fuses, and similar items are noted.
Careful observation is also made of reflectors which appear
to need washing and any other points which might affect the
efficiency of the system, after which a report is made up about
noon and promptly sent to the maintenance department to
permit all renewals and repairs to be made before night. In
this manner the lamps are well maintained from day to day.
80. Marking columns. To facilitate this renewal work, it
has been found advantageous to mark all columns through this
shop. The inspector is thus enabled to indicate clearly the
location of each burned out lamp and the renewal man to
locate it without delay. It is helpful now and then in like
manner to have the inspector note the unnecessary lamps
found burning when artificial light is not required. If lamps
are found burning at such times, a note sent to the head of
the department calling attention to the matter, is usually
sufficient to remedy the difficulty.
81. Noting soiled reflectors. As a check on a regular
cleaning schedule the inspector should note all reflectors in
need of cleaning. The frequency of each cleaning will depend
on the rate of deterioration due to the settlement of dirt on
the surface of the glass or metal and also on the surface of
GENERAL LIGHTING SAFETY ORDERS. 57
lamps, and the fact should be kept in mind that the amount
of dirt on a reflector is nearly always deceptive, that is,
reflectors which have suffered a large deterioration in efficiency
clue to dirt often appear fairly clean, and for this reason it is
best to increase the frequency of cleaning somewhat over that
which seems sufficient from observation, particularly in view
of the fact that tests indicate large reductions of light from
apparently small accumulations of dust and dirt.
82. A method of washing. In the factory just referred to,
all reflectors are removed to a central washing point. Where
the number of reflectors to be hauled is large, a truck is used.
Often, however, where only a small number of reflectors is to
be transported, small hand racks, devised for the purpose, are
employed. When an installation is in need of washing, the
scheme is to haul sufficient clean reflectors to the location in
question. The soiled reflectors are then taken down and clean
ones immediately put into place, after which the soiled reflec-
tors are removed to the central washing point, washed and
put into stock for the next location.
EXPERT ASSISTANCE SUGGESTED.
83. The advantages of securing expert assistance in dealing
with illumination are strongly emphasized. The points which
come up for solution are complex and require, in many cases,
the judgment of one who has had wide experience in the
lighting field.
OTHER FEATURES OF EYE PROTECTION.
84. Care is urged on the part of those responsible for the
health and welfare of employees to see that adequate eye pro-
tection is afforded in all operations which are apt to cause
injury to eyesight if such protection is neglected. As typical
of such other causes of danger to eyesight, arc welding may
be mentioned, where the operator, according to accepted prac-
tice, must wear a helmet in general. Protective glasses for this
purpose should not be judged as to their protective properties
by mere visual inspection. They should, therefore, be analyzed
for their spectral transmission of invisible radiation. Pro-
tective measures should also be taken to prevent onlookers
from being unduly exposed to such eye dangers, by enclosing
58 GENERAL LIGHTING SAFETY ORDERS.
the welding operations with suitable partitions. These gen-
eral remarks apply with equal force from the standpoint of
those handling the operations to such other cases as the testing
of arc lamps, inspection of hot metal and similar cases.
GOOD AND BAD LIGHTING COMPARED.
85. In order to give an idea of good and bad lighting,
Figs. 13, 14, 26, 27, 28 and 29 are shown. These illustrations
indicate the use of various types of lamps and a reference to
the captions under the illustrations will bring out the weak
points of the poorly lighted spaces, as well as the points of
excellence in those cases which are designed in conformity
with good illumination practice.
METHOD OF MEASURING SURFACE BRIGHTNESS.
86. The candlepower of the brightest square inch of light
source may be measured by means of a portable photometer.
An opaque board with a square or circle hole one-quarter square
inch in area is placed against the surface of the light source
in such a position that the brightest spot emits light through
the hole in the board. The board must be of such size as to
prevent any other light from the source to strike the photo-
meter. The photometer is placed at some convenient distance
from the light source unit, and read, care being taken to
exclude all light from the photometer except that coming
through the hole. If the photometer is read at a distance of
one foot from the light source, the foot-candles observed multi-
plied by four will be the candlepower; if the photometer is
two feet distant from the light source, the foot-candles
observed must be multiplied by sixteen to obtain the candle-
power; if three feet, they must be multiplied by thirty-six,
etc., the observed foot-candles in all cases being multiplied
by the square of the distance times four between the light
source and the photometer, when the readings were taken to
obtain the candlepower of the source.
INDEX.
A Sub-
Page Order division
Accessories 7-8 1507
Aisles:
Minimum intensity (foot-candles) 5 1503 2
Workspace, emergency lighting of 8 1508 a
Appendix 10-58
Control of lamps and arrangement of switches. 45-48
Daylight 22-28
Effects on factory and mill lighting produced by
modern lamps 31-32
Expert assistance suggested 57
General information and suggestions 10-11
General requirements of artificial lighting 32-33
Good and bad lighting compared 58
Lighting circuits for electric lamps and supply
mains for gas lamps 44-45
Method of measuring surface brightness 58
Minimum and desirable illumination 11
Old and new lamps
Other features of eye protection 57
Overhead and specific methods of artificial
lighting _" 33-34
Reflectors and their effect on efficiency 49-51
Side light important in some factory and mill
operations 51—57
Systematic procedure should be followed in
changing a poor lighting system over to an
improved arrangement 48-49
Table of recommended intensities for detailed
operations and processes 12-22
Value of adequate illumination 28-31
Various locations illustrated 34-44
Artificial light 5-6 1503
Artificial light required 5 1501
Awnings, shades, diffusive or refractive glass 5 1502 b
B
Brightness :
Definition of 4 1500 h
Sky 5 1502 a
C
Candle, definition of 4 1500 a
Candlepower, definition of 4 1500 a
Coarse work, minimum intensity (foot-candles) 6 1503 4
Committee on General Lighting Safety Orders 3
Control of emergency lighting 8-9 1508 d
Control and switching apparatus, installation 9 1509 a
Control and switching apparatus on emergency,
identification 9 1509 b
D
Definitions 4-5 1500
Brightness 4 1500 h
Candle 4 1500 a
Candlepower 4 1500 a
Eyestrain 4 1500 j
Foot-candle 4 1500 c
Foot-candles at floor-level 5 1500 o
Foot-candles at the work 5 1500 n
60
INDEX.
D — Continued.
Definitions — Continued.
Glare ___J
Illumination
Intensity of illumination
Lamp
Lamps, local
Lamps, overhead
Local lamps
Lumen
Overhead lamps
Photometer
Shaded
Detail, discrimination of, minimum intensity (foot-
candles)
Diagram illustrating shading of lamps for overhead
lighting
Diffusive window glass
Distribution of illumination uniform
Distribution of light on work
Drafting, minimum intensity (foot-candles)
Dressing rooms, minimum intensity ( foot-candles )__
Elevator cars, minimum intensity (foot-candles)
Elevator entrances, minimum intensity (foot-
candles)
Emergency lighting
Controlling equipment
Exits
Hospitals
Installation of
Intensity of (minimum)
Moving picture exhibition places
Outside landings of fire escapes
Passageways
Public meeting halls
Schools
Source of supply
Stairways
Supply
Systems, including supply and branch lines
Systems, independent source
Theaters
Workspace aisles
Engraving, minimum intensity (foot-candles)
Exits:
Emergency lighting of
Minimum intensity (foot-candles).
Eyestrain
Definition of _
Fine manufacturing, minimum intensity (foot-
candles)
Foot-candle, definition of
Foot-candles at floor level, definition of
Foot-candles at the work, definition of
General requirements
Glare, definition of
Glass window, diffusive and refractive.
Sub-
Order
division
1500
i
1500
I
1500
m
1500
e
1500
f
1500
9
1500
f
1500
b
1500
9
1500
d
1500
7c
1503
4, 5, 6
1505
1502
b
1507
1507
1503
8
1503
3
1503
3
1503
2
1508
1508
d
1508
a
1508
d
1508
b
1508
c
1508
d
1508
a
1508
a
1508
d
1508
d
1508
d
1508
a
1508
d
1508
b
1508
b}d
1508
d
1508
a
1503
8
1508
a
1503
2
1502
b
1500
3
1503
7
1500
c
1500
o
1500
n
1501
1500
1
1502
b
INDEX.
H
61
Sub-
Halls and hallways, minimum intensity (foot- Page Order division
candles) 5 1503 2
Halls, public meeting, emergency lighting of 8-9 1508 d
Hospitals, emergency lighting of 8-9 1508 d
Identification of switching and control apparatus on
emergency, pilot and night lights 9 1509 &
Illumination :
Definition of 4 1500 I
Distribution of 7-8 1507
Emergency 8-9 1508
Intensity of, definition 4 1500 m
Intensity (minimum) of emergency lighting 8 1508 c
Intensity of illumination, definition of 4 1500 m
Intensities (minimum) 5-6 1503
Aisles ! 5 1503 2
Drafting 6 1503 8
Dressing rooms 5 1503 3
Elevator cars 5 1503
Elevator entrances 5 1503 2
Engraving 6 1503 8
Exits 5 1503 2
Fine manufacturing 6 1503 7
Halls and hallways 5 1503
Office work 6 1503 7
Passageways 5 1503 2
Roadways 5 1503 1
Rough manufacturing requiring discrimination
of detail 6 1503 5
Rough manufacturing requiring closer discrimi-
nation of detail 6 1503 6
Stairs 5 1503 2
Stairways 5 1503
Storage spaces 5 1503
Toilet rooms 5 1503 3
Wash rooms 5 1503
Water-closet compartments 5 1503 3
Watchmaking 6 1503 8
Work not requiring discrimination of detail 6 1503 4
Yards 5 1503 1
L
Lamp, definition of 4 1500 e
Lamps :
Local, definition of 4 1500 /
Local, shading of 7 1506
Overhead, definition of 4 1500 g
Overhead, shading of 6-7 1505
Overhead, shading of, diagram illustrating 7 1505
Landings of fire escapes (outside), emergency light-
ing of 8 1508 a
Light :
Artificial 5-6 1503
Distribution on work 7-8 1507
Measurements 6 1504
Required, artificial or natural--. 5 1501
62
INDEX.
L — Continued.
Lighting : ^
Emergency. See Emergency Lighting. Page Order division
Local, shading of 7 1506
Natural 5 1502
Overhead, shading of 6-7 1505
Roof 5 1502 a
Skylights 5 1502 a
Windows 5 1502 a
Lights, night and pilot:
Identification 9 1509 &
Installation of 9 1509 a
Local lamps, definition of 4 1500 f
Local lighting, shading of lamps for 7 1506
Lumen, definition of - 4 1500 6
M
Manufacturing, minimum intensity (foot-candles) :
Fine 6 1503 7
Rough 6 1503 5, 6
Measurements 6 1504
Minimum intensities 5-6 1503
Moving picture exhibition places, emergency light-
ing of 5 1502
N
Natural lighting 5 1502
Natural light required 5 1501
Night lights :
Identification 9 1509 &
Installation of 9 1509 a
O
Office work, minimum intensity (foot-candles) 6 1503 7
Outside landings of fire escapes, emergency light-
ing of 8 1508 a
Overhead lamps, definition of 4 1500 g
Overhead lighting, shading of lamps for 6-7 1505
Overhead lighting, shading of lamps for, diagram
illustrating 7 1505
Passageways : P
Emergency lighting of 8 1508 a
Minimum intensity (foot-candles) 5 1503 2
Photometer :
Definition of 4 1500 d
Standardized 6 1504
Pilot lights:
Identification 9 1509 &
Installation of 9 1509 a
Public meeting halls, emergency lighting of 8-9 1508 d
R
Reflectors and accessories 7—8 1507
Refractive window glass 5 1502 &
Requirements, general 5 1501
Roadways, minimum intensity (foot-candles) 5 1503 I
Roof-lighting 5 1502 a
Rough manufacturing, minimum intensity (foot-
candles) 6 1503 5, 6
INDEX.
63
c
Schools, emergency lighting of --------------------
Shaded, definition of _____________________________
Shades __________ 1 _______________________________
Shading of lamps for local lighting ________________
Shading of lamps for overhead lighting ------------
Shading of lamps for overhead lighting, diagram
illustrating _______________________________
Skylight lighting ________________________________
Stairs, minimum intensity (foot-candles) __________
Stairways :
Emergency lighting of ------------------------
Minimum intensity (foot-candles) _____________
Storage spaces, minimum intensity (foot-candles) __
Summary of safety provisions _____________________
Switches or controlling apparatus, installation of ___
Switching and control apparatus __________________
On emergency identification ------------------
Page
8-9
4
5
7
6-7
Sub-
Order division
1508 d
1500 k
1502 b
1506
1505
7 1505
5 1502 a
5 1503 2
8 1508
5 1503
5 1503
3
9 1509
9 1509
9 1509
Theaters, emergency lighting of ___________________ 8-9 1508 d
Toilet rooms, minimum intensity (foot-candles) ____ 5 1503 3
Traversed spaces ________________________________ 5 1501
W
Wash rooms, minimum intensity (foot-candles) ____ 5 1503 3
Watchmaking, minimum intensity (foot-candles) ___ 6 1503 8
Water-closet compartments, minimum intensity
(foot-candles) ____________________________ 5 1503 3
Window glass, diffusive and refractive _____________ 5 1502 b
Windows, skylights or other roof-lighting construc-
tion of buildings ___________________________ 5 1502 a
Work of coarse nature, minimum intensity (foot-
candles) ---------------------------------- 6 1503 4
Working spaces _________________________________ 5 1501
Workspace aisles, emergency lighting of __________ 8 1508 a
Yards, minimum intensity (foot-candles) __________ 5 1503
APPENDIX. For table of contents see "Appendix" listed in index.
47806 10-19 6M
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